The present invention relates to an installation for generating energy.
U.S. Pat. No. 5,669,217 and EP 1 039 115 each disclose an installation for generating energy having a compressor assembly for compressing air. The compressor assembly comprises:
a low-pressure compressor having an air inlet and an outlet,
a high-pressure compressor having an inlet and an outlet, the outlet of the low-pressure compressor being connected to the inlet of the high-pressure compressor via a primary air path,
a compressor turbine assembly for driving the low-pressure compressor and/or the high-pressure compressor, which compressor turbine assembly comprises a single compressor turbine or a plurality of compressor turbines arranged in series, and which compressor turbine assembly has an inlet and an outlet, the inlet being connected to the outlet of the high-pressure compressor.
The known installations further comprise cooling means for cooling the air at a location which lies upstream of the outlet of the high-pressure compressor and a combustion device for burning a suitable mixture of compressed air and a fuel.
The known installations further comprise a power turbine with a rotatable shaft for delivering mechanical energy, which power turbine has an inlet, which is connected to the outlet of the compressor turbine assembly, and an exhaust-gas outlet. Also provided is an exhaust-gas pipe system, an inlet end of which is connected to the exhaust-gas outlet of the power turbine.
In these known installations, the cooling means for cooling the air between the low-pressure compressor and the high-pressure compressor are designed as water injection means.
As is known from the prior art, there are various reasons for using water injection in an installation of this type. One important reason is that the water injection creates the possibility of achieving a higher efficiency of the installation. Another reason is the possibility of reducing the polluting emissions from the installation.
It should be noted that the term xe2x80x9cwater injectionxe2x80x9d in the context of the present invention incorporates any form of injection of water, i.e. including the atomisation of water, the injection of preheated water or of steam, etc.
With the installations, which have become known to date, the advantageous effects referred to above cannot be achieved to a satisfactory extent.
A first object of the present invention is to propose measures, which lead to an improved installation.
In particular, it is an object of the invention to provide an installation with a higher efficiency than the known installations of the type described in the preamble.
Another object of the invention is to propose measures through which optimum use is made, for the heating/evaporation of the injected water, of the heat in the exhaust gases from the installation.
Yet another object is to provide an installation with lower polluting emissions than the known installations of the type described in the preamble.
Yet another object is to provide an installation in which optimum operating conditions are created for one or more of the components of the installation, which is advantageous, for example, for the technical implementation of the relevant component(s).
The present invention provides an installation for generating energy, which is characterized in that a secondary air path is provided, which, at an inlet end thereof, is connected between the outlet of the low-pressure compressor and the inlet of the high-pressure compressor, in such a manner that, of the compressed air originating from the outlet of the low-pressure compressor, a primary airflow passes to the high-pressure compressor and a secondary airflow passes into the secondary air path, and in that at the secondary air path there are first water injection means for injecting water into the secondary airflow, and in that the secondary air path, at an outlet end thereof, is connected to the connection between the outlet of the compressor turbine assembly and the inlet of the power turbine.
Dividing the airflow originating from the low-pressure compressor into a primary airflow and a secondary airflow allows optimum operating conditions to be achieved for the high-pressure compressor, while it is also possible for effective injection of water into the secondary airflow to take place. In this case, the cooling means which cool the primary airflow may likewise be designed as water injection means which, however, are independent of the water injection means for the secondary airflow.
Preferably, the primary airflow is greater than the secondary airflow; by way of example, the primary airflow is 70-90% and the secondary airflow 10-30% of the total airflow delivered by the low-pressure compressor.
The secondary airflow is combined with the primary airflow downstream of the compressor turbine assembly, so that this secondary airflow can be kept at a relatively low pressure. If the pressure at the point where the two airflows are combined is higher than at the outlet of the low-pressure compressor, it is possible to provide a fan, an auxiliary compressor, which imparts a higher pressure to the secondary airflow. By way of example, this fan is an electrically driven fan.
Preferably a heat exchanger is provided which effects a heat transfer between the exhaust gases in the exhaust-gas pipe system, on the one hand, and the secondary airflow, on the other hand, preferably downstream of the first water injection means. In this way, it becomes possible for as much water as possible to be introduced into the secondary airflow and to be evaporated using the heat from the exhaust gases.
It should be noted that, within the context of the description, which follows, and the claims, numerical words are used, such as first, second, third, etc. These numerical words are used only to identify the separate components, and do not provide any indication of the number of similar components which is or should be present in the installation. For example, it is conceivable to produce an installation in which the fourth heat exchanger, which is yet to be described, is absent, yet the fifth and sixth heat exchangers, which are yet to be described in more detail, are nevertheless present.
Further advantageous embodiments of the installation according to the invention are described in the claims and the following description which is based on the drawing.